This invention relates generally to angioplasty and particularly angioplasty guiding catheters and methods for performing angioplasty on patients.
Coronary angioplasty procedures are known to cardiologists and they involve generally translating a guide wire and balloon catheter through a guiding catheter that has been routed through a patient's cardiovascular system, and positioning the balloon proximate a constricted portion of a blood vessel. Hydraulic pressure is then applied through the balloon catheter to bias against the vessel constriction, resulting in stretching and tearing of the constriction in the blood vessel, thus enlarging the vessel lumen and allowing more blood flow distal the constriction.
In order to deliver or direct a balloon catheter assembly into a blood vessel, the guiding catheter is made of stiffer material than is needed to seat itself in the ostium of the blood vessels. Guiding catheters are known to cardiologists and are constructed in an assortment of different configurations to fit various vessels, such as coronary arteries, bypass grafts and internal mammary arteries It is also known to cardiologists that guiding catheters serve two functions, namely they serve as delivery conduits for the wire and balloon angioplasty catheter assemblies, which angioplasty assemblies are of relatively delicate construction, and after an angioplasty catheter assembly is positioned proximate a constriction, the guiding catheter also provides support or pushing power to enable the physician to advance the deflated balloon assembly into and through the blood vessel constriction, so that biasing pressure can be efficiently applied and the vessel lesion can be dilated to a wider diameter.
Known angioplasty guiding catheters that are sold are constructed of layers of polymer material enclosing a wire braided support layer, which makes the catheter stiffer than one constructed solely of polymer material However, such wire supported polymer catheters do not have sufficient stiffness to overcome severe or rigid coronary obstructions or complicated, twisting curved sections of blood vessels. When such rigid obstructions or tortuous vessel curves are encountered, the guiding catheter tends to back away from the obstruction as the balloon catheter is advanced out of the guiding catheter and towards the lesion. Such lack of sufficient rigidity and stiffness in known catheters inhibits the treating physician from applying sufficient force with the guiding catheter, to allow passage of the balloon catheter across the lesion, thus rendering some lesions or other constrictions untreatable by the angioplasty technique
It is an object of the present invention to develop a guiding catheter and method for performing angioplasty, that allows greater biasing leverage for advancing balloon catheters through tortuous vessels or severe constrictions than those guiding catheters and methods for performing angioplasty previously known in that art.
It is another object of the present invention to create a guiding catheter and methods for performing angioplasty, that allows the guiding catheter to pass through twisted, tortuous sections of a patient's cardiovascular system, yet provides sufficient rigidity to prevent backing away from vessel lesion sites.
It is also an object of the present invention to develop a guiding catheter having a wide assortment of construction configurations to fit various vessels, including coronary arteries, bypass grafts and internal mammary arteries.